Back to the gearbox

Eager fans might remember the Gearbox Woes post from a while back, where I was flapping about the fact that the gearbox I had received in the Ariel kit appeared to be the wrong part number, probably from a twin or a VB, and that possibly the casing was wrong and the mainshaft too.

You might also remember that I concocted a plan to test the theory in a dummy build, to look at the chain alignments. Got all that?

Well, now that the engine is in manageable chunks, we can lift it into position in the frame and see if the sprockets line up.

To do that, we have to release the front engine plates since the curve in the crankcases means that it will not drop in from the top. Releasing these plates means that the lower frame rails are no longer tied to the front down tube and the frame is allowed to spring open - not a comfortable state of affairs, so a little support is needed from a box underneath.

With the bottom end in place, we can put all the engine studs back in position and begin to settle the engine & gearbox into position.

We swung the gearbox out of the bottom lug, since we believed that the modification Ariel had Messrs. Burman make for the Square Four was to machine the top & bottom lugs with a different offset. This proved not to be the case, and the gearbox swung back in with not problem.

We know from the parts lists that the Square Four carries different gearbox casing & mainshaft part numbers; My theory is that since the SQ4 uses a 4.00" (WM3 rim) rear tyre, and the twins and singles a 3.25" or 3.50" (WM2 rim), then the gearbox sprocket must be 1/4" further outboard of the centreline, and the mainshaft must be longer to allow the clutch to maintain it's position in relation to the gearbox sprocket. To accommodate the different widths of the tyres, see? If the SQ4 engine is wider than the twins (it is clearly wider than the singles) then the mainshaft must be even longer.

But is it? having put it all back together, we find that the gearbox sprocket appears to align with the rear wheel sprocket (as we had seen months ago) and the clutch journal on the mainshaft appears to sit in the right place in the primary drive casing.

Promising? we need to sort out the clutch to find out.

More later. 

Coming apart at the seams

Well, inspired by Mr. Frank Westworth and his tales of Thor, King of Hammers I have been caressing dear Amelias fine casings and she has finally agreed to show me her most intimate areas.

If you remember, I had released all the head fastenings and had summarily failed to separate the head from the barrel. At the suggestion of the ever helpful Brenton Roy, I released the barrel nuts which of course meant stripping down the timing chest, which all went very well.

So, one lunchtime I took hold of Amelia's head, and proceeded to lightly tap around the barrel base flange with my handly mallet, hide face of course.

Slowly, the barrel came free and I was able to lift it, supporting the pistons on timber bearers as I went. What was revealed was quite happy, as far as I can see - nothing has been measured yet. However, someone has been in there:

As evidenced by the single shiny piston! I'm not sure what is going on there but at least nothing is broken and there is no rust.

On the other side of the joint, again all seems well, but there is a lot of carbon about:

Here's each cyclinder, for the record: Number 1:

Number 2:

Number 3:

Number 4:













Next, we need to get the head off and measure up.

But first, now that we have the engine in manageable lumps, we will go and look at the gearbox again.

Can't stand the pressure...

Now, I have acquired a few bore gauges and this evening I have broken out the trusty old Moore & Wright micrometer and I have measured my oil pump. Here are the dimensions:

• Return bore diameter = 0.499" - 0.500"
• Return plunger diameter = 0.499"-0.4995"
• Feed bore diameter = 0.437"-0.438"
• Feed plunger diameter = 0.436"-0.4365"

Now, seeing as Mr Waller specified 0-1 thou clearance for the singles, I reckon my pump is in pretty good shape. I have max 2 thou clearance on the feed side and max 1 thou on the return.

The drive block is a different story. I have a block that varies 0.561-0.5635"; the 'groove' the block runs in on the feed plunger is 0.573 - up to 12 thou clearance. The return side is better, about 0.570, or max 9 thou clearance.

What do you all think of that? Good to go back in the engine?

I also took the opportunity to flatten the mating face - you will recall there were some little wobbles on the thin bottom edge. All gone now:

Feeling Pumped Now...

Except that, having removed the cyclinder base nuts in the hope that I can lift the cylinder and head together and then knock the head off from inside one of the cylinders, the block still won't shift.

So I try and turn the engine over in the vain hope that compression will break a weak base gasket joint, and then realise that as I have removed the dynamo the primary chain effectively jams the camshaft in place and I can't get it to turn over at all.

So, I must finish the job of dismantling the timing gear and the oil pump.

As I mentioned a day or two ago, the oil pump tab washers are not done up:

Not that you can see them very well in that picture. However, the pump comes off without any drama, though it is pretty tight on the studs. Here's the pump body, nicely marked '51, so it's probably the original. Slightly wobbly surface near the bottom edge:

Here are the plungers, nothing too nasty there. Some wear and light scoring - we will see what they look like with a micrometer on them later. I have nothing at the moment to measure the bores, and I will have to look at what I think the clearances ought to be since the only data I can find in Mr. Waller's book is for the singles.

Lastly, here is the whole pump ready for inspection. The check valve caps seem very stiff and whilst they appear to work I am reluctant to remove them. I really should inspect them and their seats though.



Oily Dynamo

We need to get moving on the engine and we don't have the parts to finish the refurbishment of the dynamo, so we will put them on the list for Drags & move on. Before we reassemble though it makes sense to check everything out.

So, the service manual tells us that the field coil resistance, across both field coils, is in the range 2.6 - 2.8 Ohms:
 

So we set the meter to the 200 Ohm range and short the test cables together, to reveal a resistance in the measuring equipment of 1.3 Ohms.

Now let's connect the field coils into the circuit. This reveals a total resistance of 4.0 Ohms, giving a value of 2.7 Ohms for the field coils alone. Spot on, correct to specification!

Next test - field coils to earth. Should be open circuit, hopefully...

Hey presto, no reading on the meter. Field coils good! Next job, clean the armature & the commutator. Easily done with some solvent, mildly abrasive paper and a razor saw. We'll not attempt to test this since the brushes are in very poor shape and as we said, we don't have the parts to rebuild this beast yet. Continuity tests & earth resistance tests look good though.

 

Here is a view of the brush assembly about to go back in. Clean enough for now, but not clean enough to use. We will finish that when we have some new oil seals & an idea of how this unit left the factory. Black gloss paint maybe? There is no evidence of any paint except for on the end cap:

And here is the drive end. I've re-tapped the hole for the distributor retaining bolt. Fortunately, whoever tried to put a BSF screw in there didn't try very hard and the thread recut nicely. Spare 1/4" BSW screw inserted for now, to be replaced with a stainless one when I can find one. Also, an appropriately sized (but incorrect thread) nut serves to retain the sprocket. Losing it is not an option!

Lastly, tired & oily brushes. Very worn, mangled insulating sleeves, fit for patterns only.

Dismantle, degrease, polish...

Well, I've set about polishing the timing cover, but no pictures! I've decided that I need to find some abrasive wheels to tackle the timing cover since, as you can see from the pictures it is quite discoloured & needs more grief than I can give it with a sisal mop!

So, I have moved on to the removal and resurrection of the Lucas C35SD dynamo. No problem getting it off, but I had noticed a while back that the commutator was full of fluff, leaves and oil. I had assumed that this was down to the fact that the end cover was in a bag with a lot of other parts, and not on the dynamo!

I'd bought a puller as part of the toolkit crusade, and so removing the sprocket was no problem. As we noticed a day or two ago, the nut was missing and the puller screws right on. You undo the nut you can see behind the puller, extract the sprocket, and the dynamo is then held only by the clamp.

So here it is, some hours later after dismantling & scrubbing with a small brush & white spirit. All the major parts are in good shape, with the exception of the oil seal which is completely cratered - it is now obvious why the thing is full of oil. The distributor retaining screw is noticeably bent, and is 1/4" BSF - not what I would have expected in a soft ally casting.

Here's a close up of some of the smaller parts. No wear or other nasties apparent.

 



Next job, when everything is finally clean enough, is to check out the field coils, the armature, and the bearings. The data is all contained in the handy instruction manual, so no problems there. We can then reassemble and do a motoring test before refinishing.

Next though, after a few days real work, we will probably get the abrasives out and finish the timing cover.

Is it time to strip the engine yet?

Well, what delights will we find under here? 

Since I have not been able to shift the head, despite undoing all the fasteners (no I didn't miss any) I have decided to attempt to remove the barrel & head together and biff the head off the barrel using a block of wood from underneath.

Thanks to the ever-helpful Brenton Roy for that most excellent suggestion!!

The only challenge is that now I must undo all the cylinder base flange fasteners, several of which are inaccessible due to the dynamo and the timing cover. So, off with the timing cover! Unfortunately my imperial  hex keys were not at home - so I had to wait a little while. It's interesting that someone has fitted a set of cap head screws to this engine, so it's likely that someone has been in here before - which I guess is almost inevitable on a 60 year old machine. 

However, it comes off very easily, apparently with no stripped threads, though there is a quite a lot of Red Hermetite about.

Here's what I found:

Nothing too appalling at first glance. Everything in it's proper place, nothing mangled, the chain looks good and the tensioner is all there.

It's quite dark though. Is this evidence of a lot of blow-by I wonder?

Looking a bit closer, there is quite a bit of wear where the chain tensioner bears on the case - but this is probably normal and inevitable since the blade is free to flex at this end and the chain tension forces the blade against the soft aluminium case.

I'm not too worried about that.

But see what is missing? I didn't remove the nut on the end of the dynamo drive shaft! It's gone! Thankfully, unless it is stuck to the inside of the timing cover (I haven't looked yet) it must have been lost last time the engine was apart. There doesn't appear to be any damage from it flying about inside.

What else?

This is a bit peculiar - the tab washers for the oil pump haven't been bent up.

The alloy block and the two plungers are free - we will have to see what tolerances are specified for these parts.

Next stop we need to figure out how to time the engine so we can put it back together. Then it is dynamo off, oil pump off & we will attempt to remove the barrel  What fun! I might do some polishing first through, so I can clear the bench of the rocker covers and timing case.

Number Crunching

Lest we forget: Cylinder numbering for the four, according to Mr. C.W. Waller:

Next job is to lift the head. We remove the four sleeve nuts inside the rocker boxes; we loosen the twelve nuts around the outside of the head and, using a 1/4" BSW ring spanner especially reduced to fit in a confined space as shown in the picture on the left we remove the final four nuts.

A curiosity here. The front two studs were both fitted with two nuts - one with a regular 1/4" BSF nut, the other with a reduced hex 1/4" BSF nut. One is tempted to think that was to allow a bit more room to throw a wrench around, but I suspect it was more a question of convenience - whatever came to hand. The two nuts were I guess fitted to protect the threads.

In theory, according to the book the next job is to lift the head and place two 1/8" wooden strips between the head and the block, to allow us to raise the head and then to actually remove the nuts from the twelve studs.

The operation will be something like that shown in the picture from the Floyd Clymer Ariel Motorcycle Owners Handbook (3rd Edition) shown as Figure 11 below.

Well, I hope it will. It hasn't happened yet. The head is stuck fast with the adhesion of decades of setting time of a whole tube of Hermetite, by the look of it.

I have taken the hide mallet and waved it around near the engine in a vaguely threatening manner, but I don't plan to do anything else with out a bit more thought and a plea to the AOMCC forum members.

On with the engine...

Winter draws on... and I have no lights outside, so I am only able to work on the engine until dusk. It is in the summer house with the rest of the bike until it is small enough pieces to bring inside. This is something of a pain but my view is that the enforced pace allows me time to think!

I can't wait until the new workshop is up & running!

Here it is - it's a 20' x 9' garage I have bought in the middle of Sheringham, and it has a 9' square area upstairs as well. It has a solid concrete floor, is built from breeze block and has a tiled & felted roof.

There is no power or light yet but at least it is dry.

I plan to get rid of the up & over door to make it a bit more bike-friendly, and then get UK Power Networks to provide a 100A power supply.

Anyway, this evening I have been preparing to lift the head.

I've been using the tool kit spanners I have collected, for the sake of familiarity, to back off the fasteners around the head. I've slackened off the 3/16" BSW rocker adjusters and the 1/4" BSW rocker spindles so that we don't have any accidents on the bench later, which all came apart quite easily (though they were all pretty tight, apart from one of the rocker spindles (offside rear)).

I then moved on to the head studs, and now I understand where they all are if I don't know how to get them undone! The twelve nuts under the third barrel fin were easy to find, especially the one at the front offside where the fin is missing.

The four inside the rocker boxes look straightforward, though I guess they are 3/16" BSW and I don't have a suitable tube spanner for that - over to you Mr eBay.

I guess that I will be replacing these fasteners with more from Acme Stainless, or possibly plating them.

As for the last four, two at the front and two at the back... one I got to with a small 1/4" BSW ring spanner; but they are very inaccessible. Maybe a tube spanner from above, though not at the back where the inlet manifold covers them up, or mabe a slender Britool ring spanner my grandfather gave me many years ago. I've asked my ever helpful AOMCC colleagues for advice.

Anyhow, I have ordered a couple of suitable tube spanners, and I'm off to Leeds for work tomorrow. then I have a couple of important family events... Maybe some more activity this time next week?

Labour of love

Going through the grits, page one of thousands...

There has been no time this week to take the head off yet - it is still sitting in the summer house awaiting hours of patience with an open ended spanner, but we can finish cleaning up the rocker covers.

I haven't committed to any polishing equipment yet, but with a spare hour I have started to polish the two rocker covers by hand.

Starting by scraping off the dirt with the ubiquitous credit card/hotel room key, we move on to 240 grit used wet to cut back most of the oxidation. Moving through 400, 600 & 800 stopping periodically to ensure that the whole surface is cut to the same standard.

For some reason we seem to be out of 1000 grit, but we move on to 1200.

The next step is a waste of time - we try with some Farecla G3 cutting compound, but quickly find that this will not cut aluminium. It is an excellent product for what it is made for - paint & lacquers.

For final finishing - Solvol Autosol, resulting in the shiny parts we see hereabouts. Shiny enough, not to ruin the patina of a 60 year old bike? too shiny? not shiny enough?

You be the judge.

More next time...

We're back - and it is engine build time.

Well at last. It may be nearing the end of summer, but what better time to get back up and running with the Ariel.

The Bantam is finished - it is now 12 V, and has had it's second engine rebuild. It's just carried me 25 miles around the country south of the city without missing a beat, even through a ford. It still doesn't like ticking over when it is hot though.

The Cyclemaster has been in the workshop for a look over. It is remarkably original as I had thought; it has a coaster brake and is a 25 cc model, but it has been some while with the spark plug loose and is siezed solid. I've put it aside for a rainy day as it's time to get back to the next step with Amelia, building the engine. Regular readers will remember that the gearbox is suspiciously offset, and part of the engine strip will include sitting the bottom end in the frame for an alignment check.

However today, there is not much biking time left. Just enough to make a little start and write a blog post.

So here are some rather grubby rocker covers, taken off for the first time in years, and bringing two of their studs with them.

Here they are again, after a session with some white spirit and a cloth. What I need to do now is source some polishing mops, and some advice on what compunds to use.

And here is what they revealed. Nothing apparently amiss there!

I'm going to spend the rest of the evening relaxing in front of the telly with a book. One by Mr C.W. Waller perhaps.

Drags Again...

Collecting more parts. Who knows what this vital component is?

Hallets of Canterbury

Some way back, eager readers might remember I bought my mudguards from an eBay contact and that they were from a bike supplied by Hallets of Canterbury. Well, quite by chance Marcel Hallet, great grandson of the Marcel Hallet whose name adorns a brass plate on my front mudguard got in touch. In his own words:

Afternoon Simon.

A little bit of history. Hallets was opened by my great grandfather after the war. My grandfather and his brother also worked there. It then purchased a company called Invicta Motors the dealer for Ford, who were in financial difficulty. Invicta grew and grew over the years having Ford dealers in Ramsgate, Margate, Faversham, Canterbury. Invictas was sold to a Japanese company in the early 2000's. Hallets the building you see in the photos was knocked down around 2 years ago and now has a block of flats with shops underneath.

Marcel Hallet

And there were a few famous names associated with Hallet's:

Derek Minter (born 27 April 1932) was a British former Grand Prix motorcycle road racer. After National Service in the RAF he often became a fascinated spectator at Brands Hatch and took a job with Hallets, of Canterbury, the motorcycle dealers who were to become his sponsors. The proprietor, Ray Hallet, had been a useful road race and grass track rider himself and had taken Derek to the Isle of Man to be his mechanic in the Manx Grand Prix. Eventually Minter persuaded the company to provide him with a BSA Gold Star. Twice he entered his name for races at Brands Hatch and twice he backed out, suddenly realising that it took more bravery to turn up and race rather than watch. Eventually he plucked up courage and began to show real talent.

His best season was in 1958 when he finished the year in fifth place in the 500cc world championship.In 1960, Minter won the North West 200 race inNorthern Ireland. In 1962, he won the Isle of Man 250cc Lightweight TT.

And the local motorcycle manufacturer, Norman Cycles of Ashford:

Dealer Hallets of Canterbury entered a two-rider team in the 1959 & 1960 Thruxton 500 mile races. Les Hatch (Norman employee) and John Punnet (Greengrocer) rode a factory prepared B3 Sports, engine was specially tuned by Villiers. The B3 Sports was more or less standard, they came 2nd in the 250 class in 1959. The result boosted the Norman order book by £10,000 over night.

Marcel was kind enough to let me post these splendid photographs:

A Sunbeam S7 & A Villiers twin...

An M20 and a Gold Flash:

An Ariel single and a VB:

Another M20 and a Gold Flash:

And this is the best one. Are those my mudguards? that is certainly a Mk1 Square Four, no chrome on the tank so it must be '51 on...